Mobile communication devices, such as, for example, cellular telephones, smartphones, digital audio or video players, portable navigation units, laptop computers, personal digital assistants, tablets, netbooks, or the like are becoming increasingly popular. These devices may include, for example, a variety of sensors to support a number of applications in today's market. A popular market trend in sensor-based mobile technology may include, for example, applications that sense or recognize one or more aspects of a motion of a user relative to a mobile communication device and use such aspects as a form of a user input. For example, certain applications may sense or recognize waving gestures, finger gestures, air signatures, and the like of a user and may use such gestures as inputs representing various user commands in selecting music, playing games, estimating a location, determining navigation route, browsing through digital maps or Web content, authorizing transactions, or the like.
Proximity sensors are similar to some gesture sensors on mobile communication devices in that proximity sensors may also utilize light and imagers to detect a user's proximity to the sensor. Proximity can also be used as inputs to applications on the mobile communication device, although proximity inputs typically provide less information than gesture inputs. In other words, proximity inputs are usually binary (the user is either within a detectable proximity of the sensor or not) whereas gesture inputs may correspond to detecting certain motions or actions of a user with the gesture sensor.
A drawback to currently-available light-based sensors (proximity or gesture) is that the sensors are only capable of detecting proximity or gesture within a small detection window. More problematic is that the small detection window is required to be directly over the sensor itself. This means that user inputs at the sensor can only be detected when the user places a part of their body (or some other object) directly over the sensor. Requiring the user to provide such inputs in a small detection window has, to this point, limited the usefulness of light-based sensors in mobile communication devices. In particular, most users are interacting with a keypad or touch screen of the mobile communication device and do not want to have to change their interaction zone to some other location that is not coincident with the keypad or touch screen.